app/database.py

from sqlalchemy import create_engine
from sqlalchemy.orm import declarative_base, sessionmaker
import os  # <--- This was missing!

# 1. Get the absolute path to the project folder
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
PROJECT_DIR = os.path.dirname(BASE_DIR)

# 2. Use the 'data' folder we created in Dockerfile
DATA_DIR = os.path.join(PROJECT_DIR, "data")

# 3. Create the database URL using the safe path
DATABASE_URL = f"sqlite:///{os.path.join(DATA_DIR, 'course.db')}"

engine = create_engine(
    DATABASE_URL, connect_args={"check_same_thread": False}
)

SessionLocal = sessionmaker(bind=engine)
Base = declarative_base()

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()